Crankshaft grinding tool



Aug. 29, 1939. E M. McGovERN Er AL CRANKSHAFT GRINDIG TOOL Filed July 26, 1958 ZKI 52 v25 Z4 2@ /f/ rr l &

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ATTORNEYS Patented Aug. 29, 1939 UNITED STATES PATENT OFFICE CRANKSHAFT GRINDING TOOL Application July 26, 1938, Serial No. 221,401

4 Claims.

This invention relates to crank shaft grinding tools and has for an object to provide a tool of this type in which the holder for the emery cloth or other grinding material is mounted to float in a driving pulley and is spring pressed radially toward the crank shaft during the grinding, operation to promote a more accurate grinding of the crank shaft and in less time, than hitherto possible.

A further object of the invention is to provide a device of this character in which the holder is provided with key slots and keys therein for securing respective ends of a plurality of grinding members such as emery cloth and permitting of the cloth being quickly detached and replaced when worn.

A further object is to provide a device of this character which may be formed of a few strong simple and durable parts, which will be inexpensive to manufacture, and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming part of this specication,

Figure 1 is an end elevation of a'grinding tool constructed in accordance with the invention in position to grind a crank shaft and showing the same being power driven through the medium of a belt drive. l

Figure 2 is a side elevation of the device shown in Figure 1 with portions broken away to expose the spring pressed pins for mounting the grinding material holder to float within the driving pulley.

Figure 3 is a cross sectional view taken on the line 3--5 of Figure 2.

. Figure 4 is a detail sectional view showing the 45' link connections between the sections of the pulley to permit application of the tool to a crank shaft.

Referring now to the drawing in which like characters of reference designate similar parts in the various views, the grinding tool III comprises a pulley diametrically split and having the semicircular sections connected together at one side through the medium of a link I I and pins I2 and Il. A similar link I4 is provided at the other side of the split and is connected to the segments throughlthe medium of pins I and. I6.

The pulley forms a driving member as well 'as a frame for the grinding material holder which latter comprises segmental sections I'l and I8 5 disposed in a central circular opening in the segments of the pulley. The segments of the holder are mounted to float in the pulley and are spring pressed radially toward the crank shaft 9 to be ground, through the medium of pins I9 10 disposed in radially extending sockets 20 and having respective helical springs 2I disposed in the sockets in rear of the pins and constantly urging the pins radially to engage the segments of the holder.

For yieldably connecting the holder as a unit with the pulley, pins 22 are disposed in radially extending sockets 23 formed in the pulley and are received in sockets 24 formed in the peripheral edges of the segments of the holder, as best shown in Figure 2. Through the medium of these pins rotary movement of the pulley segments relative to the holder segments is largely precluded. Helical springs 25 are mounted in the sockets 23 in rear of the pins 22 and yieldably 25 hold the pins engaged in the sockets 24 of the holder.

Key slots 26 and 21 are formed in one end of the respective segments I1 and I8 of the holder, as best shown in Figure 2 and receive a. bent end 30 of respective strips of abrasive cloth 28 and 29. The key slots receive respective keys in the nature of cotter pins 30 and 3| which bind the bent ends securely in place. By removal of the cotter pins the abrasive cloth may be readily replaced with fresh cloth when worn.

To apply the grinding tool to the crank shaft 8 to be ground, one of the pins I5 or I6 is removed and the segments of the pulley and the segments of the holder associated therewith, are rocxed open and positioned to encircle the shaft, as best shown in Figure 1. The pin is now replaced to couple the segments of the pulley together with the abrasive cloth tightly urged against the surface of the crank shaft to the A5 ground, by the spring pressed pins I9 and 22.

The pulley is provided with. a circumferential groove'32 to receive a belt 33 which may be trained over a pulley `34 adapted to be power driven through the medium of a shaft 35.

It will be understood that other grinding material may be used in lieu of the abrasive strips 28 and 29.

Since the segments I1 and I8 of the holde` are mounted to float within the segments of the 55 pulley, during rotation of the holder as a unit with the pulley the strips of abrasive material will be forced more tightly against surfaces protruding beyond the true cylindrical surface than 'ordinarily is the case, and thus a more accurate and more quickly ground surface will be eifected than hitherto possible with the use oi' conventional grinding tools.

Since the operation has been described as the description oi' the Darts progressed, it is thought that the invention will be fully understood without further explanation.

What is claimed is:

l. In a crankshaft grinding tool, the combination of a rotary frame having a central opening, a segment mounted within the opening and having an arcuate inner face, a flexible strip of abrading material mounted on the segment at one end oi' the strip, but free at the other end, said strip lying against the inner face of the segment.

2. In a crankshaft grinding tool, the combination of a rotary frame having a central opening, a plurality of segments mounted within the opening, flexible strips of abrading material mounted respectively on the segments at one end of the strip only, and lying against the inner periphery of the segment, all of the strips trailing in the same circumferential direction, whereby the strips are maintained taut as the pulley rotates with the abrasive in engagement with a shaft.

3. A crankshaft grinding tool comprising a separable driving pulley with a central opening, arcuate grinding material holders comprising segments mounted to tloat in the opening of the pulley, grinding material carried by said holders respectively, and springs pressing the segments laterally toward the axis of the pulley, there being three springs for each segment, one spring acting centrally on the segment and the others on respectively opposite sides thereof, whereby a slight rocking action of the segments is permitted.

4. A crankshaft grinding tool comprising a separable pulley comprising a driving member, means for holding the pulley closed as a complete ring, arcuate shoes mounted within the ring -having abrading material on their inner peripheries, spring pressed pins bearing against the exterior of the shoes at their centers forcing them inwardly while allowing a slight rocking action, said pins engaging recesses in the shoes to enable the pulley to drive the shoes. and Vother springs carried by the pulley engaging the shoes on opg5 posite sides of the centralengagement described.

EDWARD M. MCGOVERN. PAUL SCHRICK. 

